Floor construction



June 11, 1968 p H WANZER FLOOR CONSTRUCTION 5 Sheets-Sheet 1 Filed Oct. 28, 1966 INVENTOR: Pump H. WANZE-E.

ATTORNEYS June 1968 P. H. WANZER FLOOR CONSTRUCTION 3 Sheets-Sheet 5 Filed Oct. 28, 1966 United States Patent 3,387,422 FLOOR (IONSTRUC'IION Philip H. Wanzer, Charlotte, N.C., assignor to The Bright-Brooks Lumber Company of Charlotte,

Inc, Charlotte, N.C., a corporation of North Carolina Filed Get. 28, 1966, Ser. No. %,412 15 Claims. (Cl 52-4587) The invention relates to building constructions and more especially to an improved floor construction adaptable for use in gymnasiums, ballrooms and the like.

Gymnasium and ballroom floors are typically constructed of parallel rows of abutting hardwood floor boards. Proper floor performance and appearance require that the boards present a unitary level upper wear surface. However, typical floors constructed of the usual tongue and groove boards, each held to a subfioor by nails, have not been satisfactory in some respects. For example, nailed floors cannot adequately withstand the effect of moisture for any extended period and are thus lacking in durability.

As is well known, excess moisture causes individual boards to swell and, unless such swelling is restrained, each swollen board displaces an adjacent board relative to the sublloor. The swelling effect accumulates from board to board until one or more of the boards is forced upwardly by the accumulated pressure of adj cent boards thereagainst. Attempts to overcome this problem have included the use of expansion joints. Such joints have not been entirely successful, since their location at points where they would most effectively relieve the accumulated swelling pressure would result in undesirable gaps being formed at floor locations where they cannot be tolerated.

In attempting to overcome the problem caused by a swelling of the floor boards while obviating the need for expansion joints, it has been proposed to restrain the swelling of each board independently of the others. For example, spaced, parallel steel channels have been secured to a subfloor, with the channels extending transversely of the rows of floor boards to be secured thereon. Each board was then secured against the channel by manually attaching individual fasteners to the channels and the corresponding boards. Such fasteners have served to restrain each board against widthwise expansion, and thus, the latter construction has served to substantially eliminate accumulation of the swelling from board to board. However, such construction is prohibitively expensive, both as to cost of the shaped steel channels and fasteners, and

as to the excessive time and high labor cost required for its installation.

It is therefore an object of this invention to provide an improved floor construction which may he economically produced and installed and including novel means for supportingly interconnecting floor boards into a unitary floor without the use of nail or separately formed channels and fasteners of the character employed in the aforementioned prior art.

It is a more specific object to provide a floor construction comprising a plate, preferably of metal, and adapted for securement to a suitable base and having integral lugs thereon arranged to engage and firmly secure floor boards to said plate in such a manner as to restrain the floor boards against swelling by moisture therein.

It is a further object of the invention to provide a floor construction of the type described including resilient moisture barrier means interposed between the plate and the base so a to provide a cushion surface for the floor and minimize the transfer of moisture from the base to the floor.

In its preferred embodiment, the improved floor construction of this invention comprises a board-interconnector means overlying a base and including one or more plates having a plurality of spaced parallel rows of upwardly projectin connector lugs thereon. The logs are formed integral with the plate by a punching and shaping operation, using techniques and equipment well known in that art. A plurality of juxtaposed boards, each having a medial groove extending along each opposite side edge thereof, is positioned upon the plate. Each lug comprises a leg integrally joined at its lower end to the plate along a leg juncture line, with the leg juncture lines of all the lugs in each row being in alignment therealong. Each board is positioned between an adjacent pair of lug rows with its opposite side edges engaged by corresponding lugs in the adjacent pair of rows and with adjacent side edges of adjacent boards engaging opposite sides of the legs of lug in corresponding rows between the adjacent boards. A tongue is angularly joined to the upper end of each leg, with tongues of certain of the lugs in each row extending in one direction normal to the respective row and tongues of others of the lugs in that row extending in an opposite direction from said one direction. The tongues are so spaced from the plate that they may be positioned in corresponding grooves of the boards to hold them against the plate, while the legs of the lugs serve to maintain the boards in fixed relationship on the plate to form the floor.

Although the construction of the present invention is particularly adaptable as a fioor construction, it is to be understood that the term floor as used herein is intended to include any structure made in accordance with the present invention even though used for other purposes, such as a vertical wall or a ceiling construction.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which- FIGURE 1 is a fragmentary perspective view of a portion of a partially completed floor according to the preferred embodiment of the invention;

FIGURE 2 is a fragmentary perspective view of a floor board suitable for use in a floor construction according to the invention;

FIGURE 2A. is a fragmentary vertical sectional view showing a tongue-and-groove connection at the abutting ends of an adjacent pair of floor boards overlying a gap between adjacent interconnector plates;

FIGURE 3 is a somewhat schematic plan view of a floor construction according to the invention, omitting some of the flooring members or boards to show a preferred arrangement of a plurality of the improved boardinterconnector plates;

FIGURE 4 is an enlarged plan view of one of the board-interconnector plates of FIGURE 3, with portions thereof broken away;

FIGURE 5 is an enlarged plan view of the portion of the board-interconnector plate within the dotted lines 5 in FIGURE 4, showing a preferred arrangement of connector lugs corresponding to that arrangement shown in FIGURES l and 4;

FIGURE; 6 and 7 are transverse vertical sectional views taken along lines 6--6 and 7-7, respectively, of FIGURE 5;

FIGURE 8 is a viewsimilar to FIGURE 5, showing lugs arranged in a pattern according to another embodiment of the invention; and

FIGURE 9 is a transverse vertical sectional view taken along line 9-- of FIGURE 8.

Referring more specifically to the drawings, the floor construction according to the invention is shown in FIG- URE 1 broadly designated at 10 and comprises a base 11, such as a subfloor, which may be formed of masonry, wood flooring or beams, and to the substantially horizontal upper surface of which one or more floor support plates or board-interconnector plates, broadly designated at 12, are suitably secured, as by fasteners 13. Fasteners 13 extend into base 11 through holes 13 which are preferably provided at regular intervals in each plate 12. The plates 12 may be of any suitable material such as thin sheet metal; e.g., 18 gauge cold rolled steel.

Each plate 12 includes a plurality of uniformly spaced rows of integrally formed connector lugs 24, which project upwardly from the upper face 15 of plate 12. The distance between adjacent rows of lugs is adapted to accommodate flooring members, such as elongate hardwood boards 16, between rows. As will be later described, lugs 14 hold flooring members 16 against upper face 15 of plate 12, with members 16 arranged in rows extending parallel to the rows of lugs 14.

The area to be covered by boards 16 may be defined by means such as walls W, W (FIGURE 3). Such an area usually would be considerably in excess of the area covered by a single plate 12, so that several such plates are normally required for full coverage. A plate arrangement such as that shown in FIGURE 3 has proved convenient for this purpose, and is preferred. In that arrangement, each plate 12 is substantially rectangular in plan, being defined in length by opposite end edges l7, l7, and in width by opposite side edges l8, 18'. It is preferred that the rows of lugs 14, and any boards 16 being retained thereby, extend widthwise of each plate 12; i.e., substantially parallel to plate end edges 17, 17', although they may extend longitudinally of plates 12, if desired.

Plates 12 may be installed in a simple and expedient manner, as follows:

A datum line C first may be established extending parallel to the direction desired for the boards 15 to extend (e.g. perpendicular to wall W) and adjacent the center of the floor. An initial row of plates is then formed by positioning a first plate 12 with its longitudinal side edge 18 adjacent wall W, and with that row of lugs 14 nearest its end edge 17 aligned with datum line C. The relationship between the datum line C and the latter row of lugs'is shown in FIGURE 4 by way of illustration only.

Fasteners 13 are then installed through holes 13 to secure the first plate 12 in position. A second plate 12, which is similar to each plate 12, except that it is approximately one-half the length of each plate 12, is then positioned adjacent wall W on the other side of datum line C, with its side edge 18 substantially aligned with side edge 18 of the first plate 12, and with that row of lugs 14 nearest its end 17 parallel to datum line C and spaced from the nearest row of lugs 14 of first plate 12 by a measured distance equal to the spacing between immediately adjacent rows of lugs on plate 12. For constructive purposes, a small gap should be provided between the adjacent ends 17, 17' of plates 2, 12'. However, the gap must be of lesser width than the distance between immediately adjacent rows of lugs on each plate per se.

The gap is provided between the end edges of adjacent plates to allow for small variations in the lengths of the plates, in the linearity of their end edges l7, l7, and/ or in deviations of the end edges from parallel relation to the rows of lugs which may occur during manufacture of the plates. Accordingly, it should be noted that the distance from each end edge of each plate 12 and 12' to the adjacent outermost row of lugs 14 should be less than onehalf the distance between adjacent pairs of rows of lugs.

Following the installation of the two plates 12, 12' in the manner described, additional plates are installed in a manner similar to that of the first two plates, in which full-length plates 12 are arranged in longitudinal alignment with and at opposite ends of the first two plates l2, 12' until the initial row substantially extends across the full width of the floor. The plate 12 at each end of the plate row may be cut, if necessary, to lit properly in the space between the preceding adjacent plate 12 and the adjacent wall, such as wall W.

After completing installation of the initial row of plates, succeeding rows are installed in a manner similar to that of the initial row, and in which the plates in alternate rows, on each side of datum line C, preferably are arranged in staggered relation to the plates in intervening rows. As shown in FIGURE 3, the half-length plates 12' in the intial and succeeding alternate plate rows are positioned to extend from one side of the datum line C, and the plates 12' in the intervening plate rows are positioned to extend from the other side of datum line C. Preferably, the side edges 18, 18' 0f the plates in adjacent rows are spaced a reasonable distance apart; e.g., four inches, and define a gap G therebetween. By so spacing the plate rows, the number of plates required to cover the fioor area is reduced, while still providing adequate support for the fioor boards 16. The gaps G between the plate rows also accommodate irregularities in the side edges l8, 18' of the plates, such as are mentioned heretofore with respect to the plate end edges l7, 17'.

When the plates have thus been properly installed, the rows of lugs 14 in each plate are aligned with corresponding rows of lugs 14 in adjacent plates of adjacent plate rows, and all the rows of lugs of all the plates then extend parallel to datum line C. With the plates 12 thus arranged, the fioor area then is in condition for the installation of boards 16.

Each board 16 preferably is formed as shown in FIG- URE 2, and includes a horizontal undersurface 20 adapted to lie on upper face 15 of a plate 12, and a parallel upper face 21 adapted to serve as part of the wear surface of the finished floor 16. Board 16 (FIGURE 2) is formed with opposite longitudinal side edges 22, 23 defining the width of face 21. Opposite edges 22, 23 are provided with respective longitudinally extending medial grooves 24, 24 and the lower portions of edges 22, 23 are recessed elow the respective grooves 24, 24' to form inset surfaces 25, 25. Inset surfaces 25, 25' are horizontally spaced inwardly from the corresponding edges 22, 23 by re spective distances T for reasons later described. Grooves 24, 24' are of substantially greater depth than the recesses defined by surfaces 25, 25' and are adapted to receive therewithin horizontally disposed tongues of lugs 14, to be later described. The lower wall of each groove 24, 24' extends substantially parallel to undersurface 2t and the upper wall of each groove 24, 24' may extend at a slight angle to the lower wall as shown in FIGURES l and 2, to facilitate insertion of the tongues of lugs 14 into grooves 24, 24. The distance from undersurface 20 to the lower wall of each groove 24, 24- is indicated at D in FIGURE 2.

The undersurface 2d of each board 16 may be provided with an elongate shallow relief slot 26 extending lengthwise of board 7.6. Alternatively, undersurface 20 may be corrugated; i.e., it may be provided with a plurality of laterally spaced relief slots. Such slots may aid in minimizing distortion of the board due to swelling. The relief slots also may provide a convenient point for location of the heads of fasteners 13 (FIGURE 1).

Opposite end edges of each board 16 are provided with respective tongues and grooves so arranged that the abutting end edges of adjacent aligned boards may be interlocked. Such interlocked relationship is particularly desirable in the event that the end portions of adjacent boards are adjacent a gap G between adjacent rows of plates 12, since it strengthens the floor construction at that point. For example, the proximal end portions of two of the boards 16 are shown in FIGURE 2A overlying a gap G between the side edges 18, 18' of adjacent plates 12, and wherein the end edge of one of the boards 16 is provided with a transverse groove 27 for receiving a protruding tongue or projection 28 on the end edge of the adjacent board 16, thus interlocking the proximal ends of the boards 16.

Although plates l2, 12 are of different lengths, all the plates may be of the same construction in other respects.

Therefore, only one of the plates 12 will be described in detail. In the preferred embodiment of plate 12, the rows of lugs I4 extend transversely of the plate and a few of such rows are indicated at 30-33 in FIGURES l, 4, 5 and 7. Each such row comprises a plurality of lugs I4 spaced apart therealong, preferably at a uniform pitch or distance P (FIGURE 5) about twice the length of each lug 14 as measured along the row. Center-to-center spacing (FIGURES 6 and 7) of adjacent lug rows corresponds to the width of the faces 21 of boards 16, and all the lug rows are uniformly spaced apart throughout the length of each plate f2, 12', since all the boards used in installing a particular floor are usually of about the same width.

In the preferred embodiment, the lugs 14 in immediately adjacent rows are aligned laterally of the rows throu h out the length of the plate I2, as best shown in FIGURES 4 and 5, wherein immediately adjacent lugs are aligned with each other in a direction extending normal to the lug rows 36-33.

As best shown in FIGURE 1, each lug I4 is in the form of an upstanding leg 44} and a tongue angularly joined to the upper end of each leg. The tongues of certain lugs in each row are designated at 41R to denote that the corresponding lugs are of a right-handed configuration, and the tongues of other lugs in each row are designated at 41L to denote that corresponding lugs are of a left-handed configuration. In other words, the tongues 41R extend in one lateral direction, normal to the corresponding row, and the tongues 41L extend in an opposite lateral direction from the corresponding legs 4i). Each leg 40 is integrally joined to plate 12 at its lower end along a leg juncture line 42. The length of each leg 49, and therefore the spacing of each tongue 41R, 41L from plate 12, corresponds to distance D (FIGURE 2) of each board I6. The leg juncture lines 42 of all the lugs in a particular row are aligned along that row.

The projection of each tongue 41R, 41L is of a length slightly less than the depth of grooves 2-4, 24' in boards 16, measured from inset surfaces 25, 25 thereof. Prior to installation of boards 16, legs 40 are positioned at an acute angle relative to upper face 15 of plate 12, as is the case with the lugs as shown in rows 30, 31 of FIG- URE 1 and in all the rows 30-33 of FIGURES 5-7. Legs 4t) are bendable at leg juncture line 42., and, upon installation of boards 16, the lugs in adjacent rows are bent upwardly so that their legs 4i) are substantially perpendicular to face 15, as is the case with rows 32, 33 as shown in FIGURE 1. Thus, legs 40 then occupy vertical positions and tongues 41R, 41L occupy horizontal positions.

Preferably, although not necessarily, lugs 14 are uniformly spaced along each row with rightand 1ef-handed lugs arranged in alternation, as shown in FIGURES 1 and 5. When the lugs of immediately adjacent rows are aligned with each other in a direction extending laterally of the rows, as in FIGURE 5, it is also preferred that the righthanded and left-handed lugs are arranged in alternation along said lateral direction; e.g., along the length of the plate 12, as shown in FIGURES 5, 6 and 7.

The legs 40 of all the lugs 14 in a given row, whether right-handed or left-handed, are in alignment along that row, since the leg juncture lines 42 are aligned. Referring to row 32 of FIGURE 1, for example, tongues 41R of the right-handed lugs engage in the groove 24 of the last installed board 16, While the tongues 41L of the left-handed lugs in row 32 are in position to engage groove 24' of the board 16 next to be installed. As shown in FIGURE 1, the last installed board 16 is positioned against plate 12 between rows 32, 33, and the groove 24' along board longitudinal edge 23 is engaged by the tongues ML of said left-handed lugs in rows 33. The groove 24 along edge 22 of the last installed board is engaged by the tongues 41R of right-handed lugs in rows 32.

The recesses defined by adjacent inset surfaces 25, 25

of adjacent boards 16 accommodate the thickness of legs 40 with the upper portion of edge 23 of the last installed board 16 abutting the upper portion of edge 22 of the adjacent previously installed board 16. It is apparent therefore that the distances T at which the inset surfaces 25, 25 are spaced inwardly from the upper portions of edges 23, 23' are equal to about one-half the thickness of each lug leg 48. Another board I6 is then placed with its groove 24' in engagement with tongues 41L of the left-handed lugs in row 32. All the lugs 14- in row 31 are then forced or bent, as by a hammer or other tool, so that their legs 40 are moved to a substantially vertical or erect position. This forces the upper portion of the edge 23 of the new board In toward and into close abutting relation with the upper portion of the edge 22 of the last installed board 16, and holds the new board I6 with its undersurface 20 in flat engagement with upper face I5 of plate 12.. Subsequent boards I6 are installed in a similar manner.

Each board 16, when mounted in the manner described, is restrained from widthwise swelling by virtue of its mechanical contact with the legs 46 of lugs 14 on each side of the board. Thus, even though the board should become wet, the expansion forces resulting from swelling of the board are restrained individually for each board by the adjacent rows of lugs. Thus, there is no cumulative displacement of boards over the base II.

Additional features may be incorporated in the floor construction of the invention as circumstances may require. It is desirable to prevent or minimize the amount of moisture which may be absorbed by the floor boards 16, since excessive moisture may damage the finish of the floor or warp the floor boards. A certain resilience of the floor may also be desired. To this end, a resilient moisture barrier may be interposed between base 11 and plate 12.

As shown in FIGURE 1, the resilient moisture barrier may comprise a thin layer 45 of a moisture-impervious material, such as carbonized polyvinyl, overlying base 11, and a layer as of a resilient material, such as asphaltimpregnated cork board or the like, interposed between polyvinyl layer 45 and plates 12. Such a barrier has proved satisfactory for these purposes. Fasteners I3, which secure plates I2 to base II, pass through the resilient moisture barrier so the barrier forms a gasket seal around the fasteners 13, thus preventing moisture from leaking around the fasteners. ()ther equivalent barriers, may, of course, be used without departing from the invention. For example, a single layer resilient moisture barrier, such as 16 gauge butyl or other plastic sheet material, may be used instead of layers 45, 46.

A modified embodiment of board-interconnector means is shown in FIGURES 8 and 9 which, with the exception of the patterned arrangement of connector lugs, may be identical to the board-interconnector means of the first embodiment of the invention shown in FIGURES l and 4-7. Therefore, those parts shown in FIGURES 8 and 9 which correspond to like or similar parts shown in FIGURES l and 4-7, will bear the sa ne reference characters in order to avoid repetitive description.

It will be noted that the plate I2 of FIGURE 8 differs from that of FIGURES 1 and 4-7 in that the lugs lid in alternate rows, such as rows 39-, 32 of FIGURE are in lateral alignment, but the lugs M in intervening rows, such as rows 3-1, 33, are off-set with respect to the lateral alignment of the lugs in the alternate rows 3%, 32. Preferably, the lugs in the alternate rows 30, 32 are spaced about midway between the lateral planes of adjacent lugs in the intervening rows.

The patterned arrangement of the lugs 14 in the embodiment of FIGURE 8- may be desirable in that more space is provided laterally of each lug than is the case with the patterned arrangement of FIGURE 5, for the use of a hammer or other tool for forcing the corresponding lug into a vertical or erect position. In all other respects, the plate 12 of FIGURE 8 may be employed in the same manner as that described with respect to the plate I2 of FIGURES 1 and 4-7 and, therefore, a further description thereof is deemed unnecessary.

In the drawings and specification there have been set forth preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. Means adapted to supportingly engage and interconnect boards having longitudinally medially grooved opposite side edges to form a floor therefrom, said means comprising a plate having a plurality of spaced parallel rows of upwardly projectin connector lugs thereon, the distance between adjacent rows of said lugs being adapted to accommodate corresponding boards with corresponding lugs engaging opposite side edges of the respective boards, each lug comprising a leg integrally joined at its lower end to said plate along a leg juncture line, a tongue angularly joined to the upper end of each leg and being spaced a predetermined distance from said plate, the leg juncture lines of all the lugs in each row being in alignment along said row, and tongues of certain of said lugs in each row extending in one direction normal to said row and tongues of others of said lugs in each row extending in an opposite direction from said one direction, said tongues being adapted to be received in the grooved side edges of adjacent boards, whereby boards may be positioned between adjacent rows of said lugs and held against said plate by said lugs in forming a floor.

2. A structure according to claim ll, wherein said legs of said lugs are positioned at acute angles with respect to said plate, said legs being bendable at said leg juncture lines into a substantially perpendicular relation with said plate so that, upon positioning of boards between adjacent rows of lugs, said legs may be bent to position said tongues Within the grooved side edges of said adjacent boards to hold said boards against said plate.

3. A structure according to claim ll, wherein said Certain and said others of said lugs are arranged in alternation along each row.

A structure according to claim 3, wherein lugs in immediately adjacent rows are arranged in alignment with each other in a direction extending laterally of said rows.

5. A structure according to claim 3, wherein lugs in immediately adjacent rows are in alignment with each other, in a direction extending laterally of said rows and wherein said certain and said others of said lugs are arranged in alternation along said lateral direction.

6. A structure according to claim 3, wherein the lugs in alternate rows are in lateral alignment with each other, and the lugs in intervening rows are oil-set with respect to the lateral alignment of the lugs in said alternate rows.

7. A floor construction comprising a base, a plurality of juxtaposed boards each having a medial groove extending along each side edge thereof, board-interconnector means overlying said base and secured thereto and comprising a plate having a plurality of substantially uniformly spaced parallel rows of upwardly projecting connector lugs thereon, each lug comprising an upstanding leg integrally joined at its lower end to said plate along a leg juncture line and a tongue angularly joined to the upper end of each leg and being spaced a predetermined distance from said plate, the leg juncture lines of all the lugs in each row being in alignment along said row, tongues of certain of said lugs in each row extending in one direction normal to said row and tongues of others of said lugs in each row extending in an opposite direction from said one direction, each board being positioned between an adjacent pair of said rows of lugs with opposite side edges of each board being engaged by corresponding lugs in said adjacent pair of rows, said tongues being positioned in said grooves of said board to hold said boards against said plate, and the legs of said rows of lugs serving to maintain said boards in fixed relationship on said plate to form a floor.

8. A structure according to claim 7, wherein said board-interconnector means comprises a plurality of said plates secured to said base in adjacent relationship, each of said plates having opposed side edges and opposed end edges extending substantially transversely of said side edges with the side edges of all the plates extending in substantially parallel relationship, and immediately adjacent plates having their rows of lugs in alignment.

9. A structure according to claim 8, wherein said plates are arranged in rows with adjacent plates having proximal end edges extending substantially parallel to the rows of lugs, said proximal end edges being spaced apart and defining a gap therebetween of a width less than the distance between adjacent rows of lugs on each plate, and the rows of lugs immediately adjacent opposite sides of said ga being spaced apart substantially the same distance as adjacent rows of lugs on each plate.

19. A structure according to claim 8, wherein said plurality of plates is arranged in a predetermined pattern with adjacent edges of adjacent plates being spaced apart from each other.

11. A structure according to claim 10, wherein said rows of lugs extend substantially parallel to the end edges of said plates and wherein the spacing between adjacent side edges of adjacent plates is substantially greater than the spacing between adjacent end edges of adjacent plates.

12. A structure according to claim 11, wherein at least two of said boards are disposed in longitudinal alignment with abutting proximal ends thereof overlying the space between said side edges of two of said adjacent plates, and wherein one of said proximal ends has a groove therein and the other of said proximal ends has a tongue thereon received in said groove to strengthen the floor construction thereat.

13. A structure according to claim '7, wherein lower portions of adjacent side edges of adjacent boards define a recess therebetween, accommodating the legs of said lugs therein, and wherein upper portions of said adjacent board edges are in abutting relationship.

14. A structure according to claim '7, wherein lower portions of opposite side edges of each board are provided with respective recesses therein of a depth equal to about one-half the thickness of the legs of said lugs and accommodate corresponding legs of said lugs therein.

15. A structure according to claim 7, including resilient moisture barrier means interposed between said base and said plate.

References Cited UNITED STATES PATENTS JOHN E. MURTAGH, Primary Examiner. 

1. MEANS ADAPTED TO SUPPORTINGLY ENGAGE AND INTERCONNECT BOARDS HAVING LONGITUDINALLY MEDIALLY GROOVED OPPOSITE SIDE EDGES TO FORM A FLOOR THEREFROM, SAID MEANS COMPRISING A PLATE HAVING A PLURALITY OF SPACED PARALLEL ROWS OF UPWARDLY PROJECTING CONNECTOR LUGS THEREON, THE DISTANCE BETWEEN ADJACENT ROWS OF SAID LUGS BEING ADAPTED TO ACCOMMODATE CORRESPONDING BOARDS WITH CORRESPONDING LUGS ENGAGING OPPOSITE SIDE EDGES OF THE RESPECTIVE BOARDS, EACH LUG COMPRISING A LEG INTEGRALLY JOINED AT ITS LOWER END TO SAID PLATE ALONG A LEG JUNCTURE LINE, A TONGUE ANGULARLY JOINED TO THE UPPER END OF EACH LEG AND BEING SPACED A PREDETERMINED DISTANCE FROM SAID PLATE, THE LEG JUNCTURE LINES OF ALL THE LUGS IN EACH ROW BEING IN ALIGNMENT ALONG SAID ROW, AND TONGUES OF CERTAIN OF SAID LUGS IN EACH ROW EXTENDING IN ONE DIRECTION NORMAL TO SAID ROW AND TONGUES OF OTHERS OF SAID LUGS IN EACH ROW EXTENDING IN AN OPPOSITE DIRECTION FROM SAID ONE DIRECTION, SAID TONGUES BEING ADAPTED TO BE RECEIVED IN THE GROOVED SIDE EDGES OF ADJACENT BOARDS, WHEREBY BOARDS MAY BE POSITIONED BETWEEN ADJACENT ROWS OF SAID LUGS AND HELD AGAINST SAID PLATE BY SAID LUGS IN FORMING A FLOOR. 